The background of the invention will be discussed in two parts:
1. Field of the Invention
This invention relates to sewing machines and more particularly to an electrically operated chain stitch sewing machine.
2. Description of the Prior Art
Sewing machines utilizing a single spool of thread for making chain stitches through fabric are well known in the prior art. One such sewing machine, which is hand-operated, is shown in reissue Pat. No. 599 dated Sept. 14, 1858 and titled "Sewing Machine" T. J. W. Robertson. In this patent, the needle actuates a slider which carries the looper which is operated in a diagonal direction to the line of feed to open the loop of thread and keep it in position for the needle to pass through.
Another chain stitch sewing machine is shown in U.S. Pat. No. 21,833 entitled "Sewing Machine" issued Oct. 19, 1858 to G. W. Hubbard. In this patent, the looping hook is operated by a fixture attached to the needle-bar, the fixture including a pin adapted to pierce the cloth along with the needle, the pin driving a piston to throw open the looper.
Another such sewing machine is shown in U.S. Pat. No. 19,535 issued Mar. 2, 1858 to A. W. Sangster entitled "Sewing Machine", in which the point of the needle pushes a plunger downward to actuate the looper to create the chain stitch.
Sewing machines utilizing cartridges or cassettes for carrying a spool of thread or a spool of thread and a needle are shown in U.S. Pat. No. 3,385,247 entitled "Sewing Machines" issued May 28, 1968 to Johnson, et al., and U.S. Pat. No. 3,749,039 issued July 31, 1973 to Fritts entitled "Cassette Threading Arrangement in Sewing Machines". In U.S. Pat. No. 3,385,247 the cartridge unit has a hollow needle integral with the cartridge housing, the cartridge unit, in its entirety, being reciprocated during the sewing operation. U.S. Pat. No. 3,749,039 discloses a cassette arrangement containing the spool of thread along with a thread tensioning device, a check spring and a thread takeup member, the cassette then being inserted into the machine.
Other prior art known to applicant is listed by way of illustration, and not of limitation, in a separate communication to the Patent Office.
It is an object of the present invention to provide a cartridge for a sewing machine in which the needle reciprocates within the cartridge.
It is another object of this invention to provide a new and improved sewing machine which accomplishes a chain stitch in fabrics with a minimum number of movable parts in an uncomplicated arrangement.
It is a further object of the invention to provide means for switching off the electrical circuit for the driving motor only when the needle is fully retracted within the cardtridge.